Process for the development of exposed photographic material containing silver halide

ABSTRACT

A PROCESS FOR RAPID DEVELOPING OF EXPOSED PHOTOGRAPHIC SILVER HALIDE MATERIAL, ESPECIALLY X-RAY FIBERS IS PROVIDED. THE PROCESS CONSISTS IN FIRST TREATING THE MATERIAL WITH A STRONG ALKALI METAL HYDROXIDE SOLUTION AND THEN WITH THE DEVELOPER SOLUTION AND AFTERWARDS CARRYING OUT THE PROCESSING STEPS REQUIRED FOR FINISHING THE PHOTOGRAPH. THE DEVELOPING BATH MAY BE FOLLOWED BY A SECOND ALKALINE BATH. THIS PROCESS MAKES IT POSSIBLE TO OBTAIN STABLE IMMEDIATELY VISIBLE PICTURE SHORTLY, E.G. 14 SECONDS, AFTER EXPOSURE.

United States Patent ffi cer 3,694,209 Patented Sept. 26, 1972 3,694,209PROCESS FOR TI-E DEVELOPNENT F EXPOSED PHOTOGRAPHIC MATERIAL CONTAININGSIL- VER HALIDE Georg Schwienbacher, Zurich, Switzerland, assignor t0Ciba-Geigy AG, Basel, Switzerland 7 No Drawing. Filed Mar. 9, 1970, Ser.No. 17,967 Claims priority, application Switzerland, Mar. 14, 1969,3,879/ 69 Int. Cl. G03c 5/26 US. C]. 96-50 8 Claims ABSTRACT OF THEDISCLOSURE A process for rapid developing of exposed photographic silverhalide material, especially X-ray fibers is provided. The processconsists in first treating the material with a strong alkali metalhydroxide solution and then with the developer solution and afterwardscarrying out the processing steps required for finishing the photograph.The developing bath may be followed by a second alkaline bath. Thisprocess makes it possible to obtain stable immediately visible pictureshortly, e.g. 14 seconds, after exposure.

The present invention relates to the development of exposed photographicmaterial containing silver halide.

In various photographic applications there is a demand for the pictureto be visible as soon as possible after it has been taken and as a rulethe picture should also have good stability, that is to say it shouldnot undergo changes in storage and certainly not fade altogether. Theprocess of the present invention meets this demand especially withregard to X-ray films, irrespective of whether they are used in medicineor in technology. Especially with commercial X-ray films, which in mostcases are coated on both sides with layers having a high content ofsilver halide, the production of immediately visible images having agood stability involves considerable difiiculties.

The present invention is based on the observation that exposedphotographic material containing silver halide can be developed veryrapidly to stable images by (I) treating the material for at least /2second at a temperature within the range of from to 80 C. wiah anaqueous solution containing per litre from to 250 g. of an alkali metalhydroxide and then (2) treating the so-treated material for at least 0.1second with an aqueous solution containing per litre from 20 to 50 g. ofdeveloper substance, which latter solution has a temperature within therange of from 40 to 80 C. and a pH value from 3 to 10, after which theusual additional processing operations are carried out.

The present process can be applied to any desired material whichcontains silver halide and is advantageously free from developedsubstances. It is preferably used for the production of black-and-whitepictures, though with the requisite further steps of processing it isalso possible to obtain colour pictures. As mentioned above, the presentprocess is specially suitable for X-ray films on which it is in generaldifiicult to obtain stable immediately visible pictures that satisfyinsofar as contrast, gradation and fine grain are concerned.

According to the present invention the exposed photographic material isfirst treated in the manner described above with an aqueous solutionwhich, owing to its content of an alkali metal hydroxide, has a pH valueof greater than 10. Within the limits indicated above, the temperaturemay be freely chosen; as a rule it requires no further adjustment sothat it is in most cases possible to work at room temperature since allthat is needed in this connection is to impart a high pH value to thephotographio material and to ensure that as yet no chemical reactionstake place. The minimum treatment period of /2 second can be lengthenedwithout adversely affecting the result, but as a rule there is nooccasion to extend the treatment time beyond 2 seconds.

After the treatment of the material with the alkali metal hydroxide thematerial is treated with the developer substance for which purpose anydesired developer may be used, for example, pyrocatechol,para-methylaminophenol sulphate, 1-phenyl-3-pyrazolidone or preferablyhydroquinone. It is, of course, also possible to use a mixture ofdiiferent developers; for example, the developer substance may consistpredominantly of hydroquinone to which a small proportion ofl-pheuyl-3-pyrazolidone or para-methylaminophenol sulphate has beenadded. As is known strong contrasts are obtained with hydroquinone,while para-methylaminophenol sulphate and 1-phenyl-3-pyrazolidone givelow contrasts. The total content of developer substance in the solutionis from 25 to 60 g. litre and the pH value ranges from 3 to 10. Thesolution should have a temperature ranging from a minimum of 40 C. to amaximum of C. A temperature within the range from 60 to 70 C. has provedspecially suitable. For the treatment with the developer solution a veryshort time of residence, ranging from 0.1 to 2 seconds, is adequate.

After having been treated with the developer the photographs can befinished off in the usual manner though it is as a rule veryadvantageous at this stage to treat the photographic material once morewith an aqueous alkali metal hydroxide solution; this solution, whichalso has a pH value above 10, contains 20 to 250 g. of alkali metalhydroxide per litre and has a temperature from 10 to 80 C. Thistreatment, too, requires only a short time of contact of 0.1 second andas a rule no advantage is gained by extending it beyond 2 seconds.

For finishing oil the photograph the material is further processedimmediately after the treatment with the developer or the secondtreatment with alkali metal hydroxide so that the development of imagesilver ceases; this can be done by a method 'known per se, for exampleby converting the unreduced silver halide into a silver compound that isinert towards the developer substance, or by converting it into awater-soluble sil'ver compound which is then washed out. As examples ofsuch agents there may be mentioned thiourea, sodium thioglycollate, athiocyanate or thiosulphate. From among the last-mentioned salts, forexample, potassium or sodium thiocyanate or potassium thiosulphate andespecially ammonium thiocyanate and sodium thiosulphate come intoconsideration. In general, it is specially advantageous to use a mixtureof a thiocyanate with a thiosulphate. These stabilising or fixingsolutions may have the usual concentrations and contain, for example 30to 250 g. of thiocyanate and 10 to 200 g. of thiosulphate per litre ofaqueous solution. It is advantageous to work at a temperature rangingfrom 20 to 80 C, and the time in which the photographic material is incontact with these solutions is, for example, /2 to 20 seconds. It mayalso be advantageous to work with separate solutions by treating thephotographic material first with a thiocyanate solution and then with athiosulphate solution. The pictures obtained by this method arespecially stable.

The individual treatment baths may contain further substancesconventionally used for the production of photographs. Thus, it is ingeneral advantageous to incorporate a hardener for gelatine in the usualquantity, for example formaldehyde with at least one of the solutionsmentioned above. 'It is of advantage if the first alkali metal hydroxidesolutionand, when used, also the second-contains a hardener. Ananti-fogging agent, for

example S-nitrobenzimidazole, is advantageously incorporated with thefirst alkali metal hydroxide solution. Furthermore, the individualsolutions, such as first alkali metal hydroxide solution and/or thedeveloper solution, may contain sodium sulphite or metabisulphite. Anaddition of potassium bromide to the developer solution may also beadvantageous.

After having stabilised or fixed the photograph, the material is washedin water, for example for 2 to 20 secconsisting essentially of per liter20-250 g. of sodium or potassium hydroxide, having a pH value greaterthan 10;

(2) for 0.1 to 2 seconds with anaqueous solution containing per liter20-60 g. of developer substance selected from the group consisting ofpyrocatechol, para-methylaminophenol sulphate, 1-phenyl-3-pyrazolidoneand hydroquinone, this solution having a temperature from 40-80 C. and apH value of 3-10, and

onds in water heated at 30 to 80 C., and finally dried 1 (3) once againfor 0.1 to 2 seconds at 10-80 C. with in a current of air having atemperature of from 50 to an aqueous solution consisting essentially of'20-250 g. 90 C. of sodium or potassium hydroxide per liter,

The following table summarises the present process; any and thereaftercarrying out the stabilizing or fixing steps feature essential to theinvention is underlined. needed to finish off the photograph.

Tempcra- Content, Duration ture in Treatment step g./1itre in sees. 0.pH value Additives 1 Alkali metal hydroxide (NaOH). 20-250 %-2 10-80 10Hardener (OHZO); anti- Iogging agent (ti-nitrobcnzimidazole) 2 Developersubstance (hydroquinone) 20-60 0.1-2 40-80 3-10 Arggoxidan; (Na2SO 8.2 52.1 Alkali metal hydroxide 20-250 0.1-2 -80 10 Hardener (CHZO). 3Finishing 0 3.11 Thiocyanate (NHtCNS) 30-250 20-80 3.12 Thiosulphate(Nazszoa) 10-200 %-2 20-80 3.13 '1lfiocgagagte and thiosulphate (NHlCNSplus %-20 20-80 3.2 Washing in water 2-20 30-80 3.3 Drying (current ofhot air) 2-20 50-90 To enable the present process to be carried outsuitably, that is to say to turn the exposed material into the finished30 picture in a minimum of time, suitable apparatus is needed for thetreatment with the requisite solutions. For example, the individualsolutions may be sprayed on one after the other. It is especiallyadvantageous to apply the solutions by roller apparatus.

The following example illustrates the present invention.

EXAMPLE An X-ray film, compirsing on both sides a silver bromide gelatinemulsion containing on each side 18 g. cf silver nitrate per squaremetre in the silver bromide, is successively terated with the followingsolutions:

(a)[1.] for 1 second at C. with 1000 parts of water 60 parts of NaOH 20parts of aqueous formaldehyde, 37% strength (b) [2.] for 1 second at 70C. with 1000 parts of water 50 parts of hydroquinone 3 parts of1-phenyl-3-pyrazolidone 20 parts of sodium sulphite, anhydrous (c) [2.1]for 1 second at 50 C. with 1000 parts of water 60 parts of NaOH 20 partsof aqueous formaldehyde, 37% strength ((1) [3.1] for 3 seconds at 50 C.with 1000 parts of water 200 parts of ammonium thiocyanate 50 parts ofsodium thiosulphate parts of aqueous formaldehyde, 37% strength.

The material is then treated for 3 seconds with water heated at 40 C.[3.2] and finally dried for 5 seconds in a current of air heated at 70C. [3.3]. After this treatment, taking a total of 14 seconds, a stable,very contrasty and very black picture is obtained.

I claim:

1. A process for developing exposed X-ray photographic materialcontaining silver bromide, which comprises: treating the material:

(1) for /2 to 2 seconds at a temperature within the range of from 10-80C. with an aqueous solution 2. A process as claimed in claim 1, wherein,after having been treated according to claim 1, the X-ray photographicmaterial is treated with a stabilizing or fixing solution, said solutionbeing applied for at least 0.1 second.

3. A process as claimed in claim 1, wherein the material is finallywashed in water for a short time and then dried at an elevatedtemperature.

4. A process as claimed in claim 1, wherein the time of residence in thefirst or second alkali metal hydroxide bath, in the developing bath andin the bath that finalises the development is at most 2 seconds, thetime of washing in water is at most 4 seconds and the drying operationis at most 7 seconds.

5. A process as claimed in claim 1, wherein the aqueous solution (2)contains per litre 20 to 50 g. of developer substance.

6. A process as claimed in claim 2, wherein the fixing solution containsammonium thiocyanate.

7. A process as claimed in claim 2, wherein the fixing solution containssodium thiosulphate.

8. A process as claimed in claim 1, wherein at least one of theprocessing baths contains a hardener for gelatin.

References Cited UNITED STATES PATENTS 1,956,230 4/1934 Schmidt 96502,384,663 9/ 1945 Weissberger 9650 3,155,506 11/1964 Blake 96 503,168,400 2/1965 Blackmer 9666 3,232,761 2/1966 Allen 9666 3,266,8988/1966 Levy 9650 3,284,199 11/1966 Matfet 9666 3,345,174 10/1967 Dotson9661 3,404,981 10/1968 Harris 9650 3,545,971 12/1970 Barnes 96613,556,789 1/1971 Johnson 9650 PT NORMAN G. TORCHIN, Primary Examiner J.R. HIGHTOWER, Assistant Examiner US. Cl. XJR. 9663. 66

